As the first of the four phases in the project lifecycle, Inception is about understanding the project scope and objectives and getting enough information to confirm that the project should proceed - or to convince you that it should not.

The purpose in this phase is to achieve concurrence among all stakeholders on the lifecycle objectives for the project.

There are four objectives of the Inception phase that clarify the scope, project objectives, and feasibility of the
intended solution [KRO03]:

Understand what to build. Determine an overall vision,
including the scope of the system and its boundaries. Identify the stakeholders:
who is interested in this system and what are their success criteria?

Identify key system functionality. Decide which requirements are most critical.

Determine at least one possible solution. Assess whether
the vision is technically feasible. This may involve identifying a
candidate high-level architecture or doing technical prototypes, or both.

Understand the high-level estimate for cost, schedule, and risks associated with the project.

Key considerations

Projects may have one or more iterations in the Inception phase. These are
among the reasons for multiple iterations:

Project is large, and it is hard to define its scope

Unprecedented system

Too many stakeholders with competing needs and complex relationships

Major technical risks demand the creation of a prototype or proof of concept

There are some commonly observed counterproductive patterns during the
Inception phase. Some teams postpone providing estimates until they analyze
the entire domain and have written a large amount of requirements documentation.
This behavior often leads to "analysis paralysis." Another pattern
is poor planning of Inception iterations. Avoid such patterns by planning iterations
during Inception in a way that iterations are risk-driven, include early integration
and testing, and produce a product increment that you can demonstrate to stakeholders.
By default, have one (potentially short) iteration in Inception to avoid analysis
paralysis.